A modular cellphone or ‘smartwatch’ called Phonebloks can be modified by replacing wristband links or cellphone components with electronic modules each having different functionality, including microphone; motion sensor; gesture control; GPS; heart monitor; blood oxygen monitor; environment sensor; fingerprint scanner; audio jack; camera; extra battery; concealed USB stick; NFC chip for contactless payments; flashlight; programmable button; SIM port; and kinetic charging. A similar or related design concept sponsored by Google is called Project Ara.
Cellphone cases can include sensors for measuring body parameters, including for example, the cases shown in U.S. Patent Publications 2014/0200054 for vital signs, and 2014/0106676 for glucose monitoring.
Cellphone cases, can provide other attachments, including for example the cases shown in U.S. Pat. No. 8,838,037 for humidity sensing, and U.S. Patent Publication 2014/0141838 for an exchangeable display.